Adds plumbing to pass WebUI mojo::Handle from browser to renderer

content/browser/renderer_host/render_process_host_mojo_impl.cc

Index: content/browser/renderer_host/render_process_host_mojo_impl.cc
diff --git a/content/browser/renderer_host/render_process_host_mojo_impl.cc b/content/browser/renderer_host/render_process_host_mojo_impl.cc
new file mode 100644
index 0000000000000000000000000000000000000000..aca9493071c1416192033a0fbc1dbe5fdc176453
--- /dev/null
+++ b/content/browser/renderer_host/render_process_host_mojo_impl.cc
@@ -0,0 +1,93 @@
+// Copyright 20124 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/browser/renderer_host/render_process_host_mojo_impl.h"
+
+#include "base/platform_file.h"
+#include "content/common/mojo/mojo_channel_init.h"
+#include "content/common/mojo/mojo_messages.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/render_process_host.h"
+#include "mojo/embedder/platform_channel_pair.h"
+
+namespace content {
+
+namespace {
+
+base::PlatformFile PlatformFileFromScopedPlatformHandle(
+    mojo::embedder::ScopedPlatformHandle handle) {
+#if defined(OS_POSIX)
+  return handle.release().fd;
+#elif defined(OS_WIN)
+  return handle.release().handle;
+#endif
+}
+
+}  // namespace
+
+struct RenderProcessHostMojoImpl::PendingHandle {
+  PendingHandle() : view_routing_id(0) {}
+
+  int32 view_routing_id;
+  mojo::ScopedHandle handle;
+};
+
+RenderProcessHostMojoImpl::RenderProcessHostMojoImpl(RenderProcessHost* host)
+    : host_(host) {
+}
+
+RenderProcessHostMojoImpl::~RenderProcessHostMojoImpl() {
+}
+
+void RenderProcessHostMojoImpl::SetWebUIHandle(int32 view_routing_id,
+                                               mojo::ScopedHandle handle) {
+  base::ProcessHandle process = host_->GetHandle();
+  if (process != base::kNullProcessHandle) {
+    CreateMojoChannel(process);  // Does nothing if already connected.
+    if (!render_process_mojo_.is_null()) {
+      render_process_mojo_->SetBrowserWebUIHandle(view_routing_id,
+                                                  handle.Pass());
+      return;
+    }
+  }
+
+  // Remember the request, we'll attempt to reconnect once the child process is
+  // launched.
+  pending_handle_.reset(new PendingHandle);
+  pending_handle_->view_routing_id = view_routing_id;
+  pending_handle_->handle = handle.Pass();
+}
+
+void RenderProcessHostMojoImpl::OnProcessLaunched() {
+  if (pending_handle_) {
+    scoped_ptr<PendingHandle> handle(pending_handle_.Pass());
+    SetWebUIHandle(handle->view_routing_id, handle->handle.Pass());

[darin (slow to review), 2014/03/21 00:04:52]

nit: it might be nice to assert that pending_handle_ is indeed null after
calling SetWebUIHandle here.

[sky, 2014/03/21 03:19:16]

It's possible that it isn't. Say if channel initialization fails.

+  }
+}
+
+
+void RenderProcessHostMojoImpl::CreateMojoChannel(
+    base::ProcessHandle process_handle) {
+  if (mojo_channel_init_.get())
+    return;
+
+  mojo::embedder::PlatformChannelPair channel_pair;
+  mojo_channel_init_.reset(new MojoChannelInit);
+  mojo_channel_init_->Init(
+      PlatformFileFromScopedPlatformHandle(channel_pair.PassServerHandle()),
+      BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO));
+  if (!mojo_channel_init_->is_handle_valid())
+    return;
+  base::PlatformFile client_file =
+      PlatformFileFromScopedPlatformHandle(channel_pair.PassClientHandle());
+  host_->Send(new MojoMsg_ChannelCreated(
+                  IPC::GetFileHandleForProcess(client_file, process_handle,
+                                               true)));
+  ScopedRenderProcessMojoHandle render_process_handle(
+      RenderProcessMojoHandle(
+          mojo_channel_init_->bootstrap_message_pipe().release().value()));
+  render_process_mojo_.reset(render_process_handle.Pass(), this);
+}
+
+}  // namespace content